you had two questions , I didnt copy and paste the answer for both , I just gave you an example to an answer for one of your questions . You seemed to miss the entire first line of my post , here it is again :

Apologies , I read the answer to your other question in another thread regarding the competition , not the competition page , anyway the sketchfab head of community addressed this very question in that thread eg :

“Yes, fan-art is allowed, but always provide credits to the original.”

so there is your answer, sorry for the confusion again , I will ask the head of community to update the official competition page with this info